Metal drawing machine

ABSTRACT

Draw bench for rods and pipes having a carriage movable axially on a bed. The carriage is moved back and forth by compression and tension rods arranged in the machine bed. One end of the rods connects to the carriage and the opposite end is interposed between a frictional roller drive secured at a fixed location.

United States Patent [191 Pfeiffer METAL DRAWING MACHINE v [75] Inventor: Hans Pfeiffer, Solingen-Wald,

Germany [73] Assignee: Th. Kieserling & Abrecht, Solingen,

Germany [22] Filed: May 13, 1971 [21] Appl. No.: 143,019

[30] Foreign Application Priority Data May 19, 1970 Germany P 20 24 273.3

[52] US. Cl. 72/287 [51] Int. Cl. B2lc 1/28 [58] Field of Search 72/274, 285, 287,

[56] References Cited UNITED STATES PATENTS 10/1875 Farmer 72/285 10/1956 Hallden 72/285 June 19, 1973 2,536,637 1/1951 Garwig 72/291 323,619 8/1885 Allderdice 72/291 3,175,385 3/1965 Mitchell et a1 72/291 3,250,362 5/1963 Mitchell 72/291 1,765,047 6/1930 Belles 72/291 2,674,367 4/1954 White et a1. 74/2'7 FOREIGN PATENTS OR APPLICATIONS 99,158 9/1961 Netherlands 72/287 Primary Examiner-Charles W. Lanham Assistant Examiner-Michae1 J. Keenan Attorney-Edward E. Sachs [57] ABSTRACT Draw bench for rods and pipes having a carriage movable axially on a bed. The carriage is moved back and forth by compression and tension rods arranged in the machine bed. One end of the rods connects to the carriage and the opposite end is interposed between a frictional roller drive secured at a fixed location.

9 Claims, 7 Drawing Figures PATENHU 3.739.621

sum 3 or 7 Fig. 3

INVA'NTOR F IQaId'IJq T PAIENTH; m 1 91915 SHEET 7 BF 7 INVENT'OR l/AM: fire/ METAL DRAWING MACHINE The invention relates generally to a metal working machine for drawing elongated workpieces such as rods or pipes and, more particularly, to a drawing ma chine in which the draw carriage is adapted to be moved back and forth by tension or compression means secured in the bed of the machine.

The output capacity of modern multiple drawbenches for workpieces, such as rods or pipes, is already considerable by virtue of automatization of these drawbenches. However, the efficiency of chain operated carriages remains unsatisfactory, because the attainable drawing speed is too low, and the carriage idle time is too long. In the art idle time denotes the time required for the carriage to return to its starting position in front of the dieblock after one drawing operation. The time required for the loading cycle, i.e. to bring the next batch of material to be drawn to the work position in front of the dies is, in fact, substantially less than the time required to return the carriage to its position in front of the dieblock. Thus, an increase in the return speed of the carriage, to an extent that the said carriage can be returned to its starting position within the loading time, would result in a sig nificant increase in the output of drawbenches of the above described type. However, because of the large mass of the carriage and of the chains, the drive motor, the time periods required for accelerating or braking are relatively high.

Cable type drawbenches are already known which in theory provide the desired high drawing and return speeds for the carriage, for example 100 and 300 m/min., respectively. However, in drawbenches of this -kind, the tensional forces that can be applied are relatively low, since otherwise the diameter of the cables and of the cable drums has to be quite big, and the relevant mass thus limits the return speed of the carriage.

Drawbenches are also already known in which the carriage is moved back and forth without the use of tension inducing members. The draw carriage is driven by a rack and pinion arrangement. The pinions are arranged on the carriage, and are driven by electric motors secured on the carriage. The pinions engage the racks provided in the bed of the machine laterally of the carriage. The carriage is supported on rollers running on tracks parallel with the racks. It has been found, however, that in the case of long drawbenches, the use of racks is uneconomical, as they are costly to manufacture and must be accurately positioned in relation to the drive means. Drawbenches of this kind have therefore not become commercially acceptable.

It has also been proposed that the thrust forces required to move the carriage be transferred by the friction between the rollers and the carriage guide tracks. With a drive of this kind, however, the required hydraulic or electrical power must be fed to the carriage from a fixed location. Although this is technically possible, it is not economically feasible.

in order to avoid the need to transfer the power to drive the carriage, or the need to transfer the frictionally induced thrust forces, either of which are required to move the carriage, the device in accordance with the invention provides for moving the carriage by means of compression and tension rods to which the thrust forces required to move the carriage are transferred by stationary drive rollers adapted to be biased against the rods. The use of compression and tension rods to drive the carriage requires only a small space, as the guidance of the rods may be partly accommodated in the bed of the loading bench. It also has the advantage that the application of power to the carriage is more reliable and less expensive than in known drawbenches in which the carriage carries its own drive means.

Another aspect of the present invention resides in a device of the type delineated above, in which, in order to press the drive rollers uniformly against the rods which are attached to the carriage, there is provided a set of two or more rollers disposed in a single plane which are bridge mounted together with their drives; the bridges are arranged to move in a vertical plane perpendicular to the bed of the drawbench and are loaded by hydraulically actuated pistons.

The rollers are preferably driven by hydraulic motors having their feed and return lines arranged in parallel and connected through check vallves to the pressure line connecting to the hydraulic cylinders, also arranged in parallel. The pistons within the cylinder are adapted to press the rollers against the compression and tension rods. This has the substantial advantage that the pressure, which has to be delivered by the pistons, automatically adjusts itself to the torque required to drive the rollers.

For a better understanding of the present invention, together with other and further objects thereof, reference is had to the following description taken in con nection with the accompanying drawings, and its scope will be pointed out in the appended claims.

In the drawings:

FIG. lis a side elevational view ofa drawbench in accordance with the invention;

FIG. 2 is a plan view partly in section, of the drawbench shown in FIG. 1;

FIG. 3 is an enlarged sectional view taken along the line A-B of FIG. 1, showing the guide for the rods in the bed of the drawbench;

FIG. 4 is a sectional view taken along line C-D of FIG. 6;

FIG. 5 is a sectional view taken along line EF of FIG. 4;

FIG. 6 is a view partly in section of the piston arrangement and of the drive rollers bearing against the rods; and

FIG. 7 is a hydraulic diagram.

Referring now to FIGS. 1 to 6, there are shown a plurality of axially spaced frame I for supporting two laterally spaced guide beds 2,2a, which in turn support a draw carriage 3 and a drive means therefor. The drive for the carriage 3 comprises compression and tension rods 4,40, arranged on opposite sides of the carriage and in each guide bed 2,2a. The rods 4,4a are rigidly connected to the carriage by arms 6,6a, which are secured to the rods by bolts 5 and extend from the rods, through a longitudinally extending slot in tubular beds 22,24, to the carriage with an L-shaped portion of each arm 6 and 6a engaging the carriage on opposite sides thereof, see FIG. 3. The opposite or far ends of the rods are clamped between a pair of drive rollers 7, see FIGS. 1 and 5, for transferring thrust forces upon the rods to move the carriage back and forth, as hereinafter explained in greater detail.

The compression and tension rods 4,4a, see FIG. 3, are slidably disposed in longitudinally extending and horizontally arranged beds 2,2a having a substantially rectangular cross-section to prevent buckling of the rods in the bed. The beds are also provided with lubricating means, not shown, which may run into channels 8,8a. Alternatively, the rods may, of course, also be supported on roller tracks in the bench bed.

In order to bias the drive rollers 7, which are arranged at a fixed location in a single plane and against axial movement, uniformly against the top and bottom faces of the rods, the rollers 7 are mounted, as shown, with their drives, in bridges 9,9a,10,10a, which are mounted, for vertical movement in a plane perpendicular to the beds 2,2a, in stationary frames 11,12. The frames are connected to beds 2,2a and movement of the bridges and the rollers housed therein, into operating position is accomplished by hydraulically actuated pistons 13 engaging the bridges 9,9a and 10,10a, see FIGS. 4 and 6, for the purpose of pressing rollers 7 against the rods 4,4a. The pistons 13 are movably arranged in cylinders 14 and secured to frames 11,12.

The rollers 7 are mounted on shafts 15 carrying a spur gear 16 and engage a spur gear 17, see FIGS. 4 and 5, secured to a shaft 18. Each shaft 18 has secured to it a worm gear 19 engaging a worm 22 secured to shafts of hydraulic motors 21,210. Each set of two rollers 7 are driven by one of hydraulic motors 21,2la. The hydraulic motor feed and return lines 23,24 are connected in parallel and are also connected, through check valves 25, 26, to pressure lines 27, 27a of parallel connected cylinders 14 for pistons 13.

The cylinders 14 also contain plate springs 28 resting against piston 13 and reacting against the cover 14a of cylinder 14. The springs 28 press the rollers against the rods 4,4a when the pressure medium in cylinders 14 is not under pressure. The pressure medium flows to and from a hydraulic station 29 through line 30 and distributor 31.

As shown in FIG. 7, three pumps are provided to supply the oil under pressure to hydraulic motors 21,2la, two of the pumps, P1 and P2, being driven by one motor M1. The third pump P3 is driven by a separate motor M2. This makes it possible to select a plurality of drawing speeds although some other combination of pumps may be provided, in order to satisfy different drawing speed requirements. Each of the pumps is connected to a pressure-regulating valve, 32,33,34, and an electromagnetically operated reversing valve, S1, S2, S3. The pumps P1, P2, P3 are also in communication, through check valves 35, 36, 37, line 38, and electromagnetically operated reversing valve S4, with feed and return lines 23, 24 to hydraulic motors 21,21a. Connected to valve S4 is a pressure-regulating valve 47 which is connected through control line 40 to an electromagnetically operated control valve S5. A second pressure-regulating valve 42 is also connected through control line 41 to control valve S1. The pressureregulating valve 32 is in communication, through control line 43, with control valve S1. The pressureregulating valve 34 is in communication, through con trol line 44, with control valve S3, and pressureregulating valve 33 is in communication, through control line 45, with control valve S2.

The method of operation is as follows:

After motors M1,M2 are switched on and control valve S4 is set to the position shown in FIG. 7, the pumps P1, P2, P3 deliver oil, initially without pressure, back to the tank. If the drawing operation is to be initiated, valve S3 is moved to a position such that the return flow of oil from pump P3 is shut off. The pressure set at pressure-regulating valve 34 then becomes effective, as the oil delivered by pump P3 through nonreturn valve 37, line 38, valve S4, and line 38a is passed to motors 21, 21a. Oil flowing from motors 21,21a can flow back into the tank through lines 24,2411, check valve 46, valve S4, and pressure-regulating valve 47, since valve S5 has previously been set to a position such that there is no pressure in control line 40, and the oil from motors 21,2111 can therefore flow without pressure through pressure-regulating valve 47. In addition, oil passes through check valve 25 and line 27 to cylinders 14 for pistons 13. The drawing carriage 3 then begins to move slowly. In order to attain the desired drawing speed, valves S1,S2 associated with pumps P1,P2 are set to shut off the return of oil to the tank. The pressure selected by pressure-regulating valves 32,33 then comes into effect. If the drawing operation is to be terminated, valves S1,S2, S3 are returned to the settings shown in FIG. 7.

Pressure-regulating valves 34,33,32 are thus set, through control lines 44,45,43, in such a manner that the oil from pumps P1,P2,P3 can flow back to the tank. In addition to this, valve S5 is set to the position shown in FIG. 7, whereby pressure-regulating valve 47 is set, through control line 40, in such a manner that the pressure to which it is set comes into effect.

The oil flowing from motors 21,2111, through line 24a, check valve 46, and valve S4 can flow back to the tank only after overcoming the pressure to which pressure-regulating valve 47 is set. This eliminates the kinetic energy of the carriage. Oil from motors 21,21a is prevented from flowing into line 38a by check valves 48,49,50. In order to maintain the pressure in cylinders 14 even during the braking operation, and thus to be able to press the rollers against rods 4,4a, a part of the oil from motors 21,21a is passed, through line 24b, valve 26, and lines 27, 27a, to cylinders 14. As soon as the carriage has come to a halt, the pressure of the oil in cylinders 14 can drop, since a portion of the oil can flow back into the tank through line 27a, choke valve 51, and leakage line 52. The fluid that may have leaked while motors 21,21a are in operation may drain away through lines 52, 53. In order that the carriage may be brought back to its starting position in front of the die block at a higher speed, valve S4 is set in such a position that line 38 is connected to line 240. At the same time, valve S5 is set in a manner that the oil subsequently to be released from motor 21a may flow back to the tank without pressure through line 38a, valve S5, and pressure-regulating valve 47, since control line 40 is without pressure.

In order that the total amount of oil delivered by pumps P1,P2,P3 may be delivered to motor 21a, valves S1,S2,S3 are set in such a manner that pressureregulating valves 32,33,34 prevent the flow of oil into the tank, and the pressure to which these valves are set may therefore come into effect. The oil then flows through line 38, valve S4, and line 240 to motor 21a which can then reach a correspondingly high r.p.m. because the flow of oil to motors 21 is prevented by check valve 46. Controllable check valves 55,56,57 are opened simultaneously through control line 54, so that the oil delivered by motors 21 the carriage rollers are driven when the said carriage returns can circulate through check valves 55,56,57 and 48,49,50.

During the return movement, the rollers must again be pressed against rods 4,4a. To this end, oil is again fed through check valve 26 and lines 27,27a to cylinders 14. The carriage returning at an'increased speed must be braked at a specific distance from the die block. As already indicated, when the carriage returns, lines 38 and 240 are connected together by an appropriate setting of valve $4. In order to make braking possible, valves S1, S2, S3 are first set in a position such that oil from pumps P1,P2,P3 can flow back to the tank without pressure, through pressure-regulating valves 32,33,34. At the same time, valve S5 is set to a position such that that control line 40 is closed off and the pressure to which pressure-regulating valve 47 is set may come into effect, i.e. not only the oil from motor 21a, but also the oil from motors 21 may flow back into the tank through pressure-regulating valve 47, as a result of which all motors and thus all rollers are braked. The oil from motors 21, which was recirculated during the re turn run of the carriage, can now no longer flow through controllable check valves 55,56,57, since these valves are now closed, there being no longer any pressure in lines 38 and 54. In order to make it possible for motors 21 to draw oil through lines 38 and 24c during the braking cycle, controllable check valve 46 is opened by the pressure obtained in line 38a, which is determined by pressure-regulating valve 47.

When the carriage-return speed has dropped to an extent that the said carriage may run against the die block without causing damage, valve 81 is set to a position such that lines 43 and 41 are connected together. However, since the pressure to which pressureregulating valve 42 is set is substantially less than that at pressure-regulating valve 32, the pressure at valve 42 comes into effect. The oil from pump P1 can therefore operate only at a low pressure. At the same time that valve S1 is reset, valve S5 is also moved to a position such that the oil can flow away without pressure through line 38a, valve S4 and pressure-regulating valve 47. This enables the carriage to arrive at the die block at a very low speed, and come to a halt; the speed being determined by the volume of oil delivered by pump P1 and the pressure set by pressure-regulating valve 42. While the carriage is abutting the die block, oil from pump Pl, upon overcoming the pressure at pressure-regulating valve 42, may flow back into the tank through pressure-regulating valve 32. After a certain length of time, valve S1 is set to allow the oil from pump P1 to flow back to the tank under no pressure through pressure-regulating valve 32, Check valves 36 and 37 prevent a flow of oil from pump P1 to pressure regulating valves 33,34 when only pump P1 is delivermg.

The setting of all valves is carried out by a known sequence control circuit which ensures fully automatic operation of the drawing cycle.

While there have been described what are at present considered to be the preferred embodiments of this in- 6 vention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is aimed, therefore, in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What is claimed is: I

l. A drawing machine for elongated workpieces such as rods or pipes, comprising:

a longitudinally extending and horizontally arranged bed;

a metal drawing carriage disposed longitudinally movable on and parallel to said bed;

rod-like tension and compression means slidably disposed within said bed and connected to said carriage;

pressure rollers and a drive therefor, said rollers being effective to be biased upon said rod-like means for transferring thrust forces thereupon to move said carriage back and forth.

2. A drawing machine according to claim 1, wherein said rollers are arranged at a fixed location adjacent to said bed.

3. A drawing machine according; to claim 1, wherein said rollers are arranged above and below said rod.

4. A drawing machine according to claim 2, wherein said rollers and the drive therefor are mounted in sets of two in bridges arranged perpendicular to the longitudinally extending plane of the bed and the rod-like means.

5. A drawing machine according to claim 1, and hydraulic piston means disposed in operating relation to said rollers for biasing said rollers against said rod-like means.

6. A drawing machine according to claim 5, wherein said drive for said rollers comprises hydraulic motors and hydraulic fluid feed and return lines connected in parallel to each other;

a cylinder housing for each piston fluid line connected in parallel;

and fluid pressure lines having a check valve and connecting said lines of said cylinder housing to said feed and return lines.

7. A drawing machine according to claim 1, wherein said bed is substantially tubular for carrying said rodlike means against buckling.

8. A drawing machine according to claim 7, said tubular bed having a longitudinally extending slot; and an arm secured to said rod-like means and projecting through said slot and engaging said carriage.

9. A drawing machine according to claim 8, wherein said bed is composed of two tubular members spaced in parallel relation with said carriage movably arranged therebetween; and said rod-like means and the con necting arm therefor in each tubular member of said bed. 

1. A drawing machine for elongated workpieces such as rods or pipes, comprising: a longitudinally extending and horizontally arranged bed; a metal drawing carriage disposed longitudinally movable on and parallel to said bed; rod-like tension and compression means slidably disposed within said bed and connected to said carriage; pressure rollers and a drive therefor, said rollers being effective to be biased upon said rod-like means for transferring thrust forces thereupon to move said carriage back and forth.
 2. A drawing machine according to claim 1, wherein said rollers are arranged at a fixed location adjacent to said bed.
 3. A drawing machine according to claim 1, wherein said rollers are arranged above and below said rod.
 4. A drawing machine according to claim 2, wherein said rollers and the drive therefor are mounted in sets of two in bridges arranged perpendicular to the longitudinally extending plane of the bed and the rod-like means.
 5. A drawing machine according to claim 1, and hydraulic piston means disposed in operating relation to said rollers for biasing said rollers against said rod-like means.
 6. A drawing machine according to claim 5, wherein said drive for said rollers comprises hydraulic motors and hydraulic fluid feed and return lines connected in parallel to each other; a cylinder housing for eaCh piston fluid line connected in parallel; and fluid pressure lines having a check valve and connecting said lines of said cylinder housing to said feed and return lines.
 7. A drawing machine according to claim 1, wherein said bed is substantially tubular for carrying said rod-like means against buckling.
 8. A drawing machine according to claim 7, said tubular bed having a longitudinally extending slot; and an arm secured to said rod-like means and projecting through said slot and engaging said carriage.
 9. A drawing machine according to claim 8, wherein said bed is composed of two tubular members spaced in parallel relation with said carriage movably arranged therebetween; and said rod-like means and the connecting arm therefor in each tubular member of said bed. 